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This paper reports the results of several experiments performed at the LULI laboratory (Palaiseau, France) concerning the propagation of large relativistic currents in matter from ultra-high-intensity laser pulse interaction with target. We present our results according to the type of diagnostics used in the experiments: 1) Kα emission and Kα imaging, 2) study of target rear side emission in the visible region, 3) time resolved optical shadowgraphy. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

The transport of relativistic electrons in solid targets irradiated by a short laser pulse at relativistic intensities has been studied both experimentally and numerically. A Monte-Carlo collision code takes into account individual collisions with the ions and electrons in the target. A 3D-hybrid code takes into account these collisions as well as the generation of electric and magnetic fields and the self-consistent motion of the electrons in these fields. It predicts a magnetic guiding of a fraction of the fast electron current over long distances and a localized heating of the material along the propagation axis. In experiments performed at LULI on the 100 TW laser facility, several diagnostics have been implemented to diagnose the geometry of the fast electron transport and the target heating. The typical conditions were: E[SUBl] ≤ 20 J, &lembda; = 1 μm, τ ≈ 300 fs, I &aysmp; 10[SUP18]-5.10[SUP19]W/cm[SUP2]. The results indicate a modest heating of the target (typically 20-40 eV over 20 μm to 50 μm), consistent with an acceleration of the electrons inside a wide aperture cone along the laser axis. [ABSTRACT FROM AUTHOR]